The present invention relates to a method of operating a computer having an audio device driver for driving sound control hardware, and a control application for interfacing the audio device driver and an audio compression manager. The present invention also relates to a computer operating in accordance with such a method.
With the advent of multimedia technology, it is now possible to conduct telephone conversations over local or wide area computer networks or even over the internet using personal computers. A number of audio communication programs are available for facilitating such conversations. Examples are NetMeeting(trademark) available from Microsoft Inc, USA, CoolTalk(trademark) from Netscape Inc, USA, and WebPhone(trademark) from NetSpeak Corporation, USA.
In general, audio communication programs are run on personal computers provided with a soundcard 1 and associated microphone 2 and loudspeaker 3. The audio communication program provides an Application Manager (AM) 4 which is interfaced through a Microsoft Windows(trademark) environment (ACM-API) 5 to an Audio Device Driver (ADD) 6 specific to the soundcard being used. This is illustrated in FIG. 1. Windows(trademark) is supplied with a number of xe2x80x98standardxe2x80x99 ADDs from which an operator may make a selection appropriate to the soundcard being used.
The main function of the AM 4 is to provide the user interface, allowing a user to perform tasks such as selecting options and services and initiating and terminating a call. The AM 4 also routes pulse code modulated (Ipcm and Opcm) audio data between the ADD 6 and an audio coding decoding program 7 generally known as an audio codec or Audio Compression Manager (ACM). The ACM 7 performs audio coding and decoding in accordance with a desired audio protocol to both compress and decompress the data and to transform it into a form suitable for transmission and reception. Compressed data (Inet and Onet) is coupled between the ACM 7 and an external network 10 via the AM 4 and a network protocol stack 8 and a network interface 9. As with the ADD, a number of different audio codecs are usually provided with the final choice being left to the user. Of course, the other party or parties to the communication must also have access to the same codec. Audio codings currently supported by ACMs include GSM, ADPCM, G.711,G.728,G.723.1.
It will be appreciated that the modular structure (4 to 8) of current multimedia applications provides maximum flexibility in terms of hardware and transmission protocols. This flexibility is essential if the multimedia applications are to be usable with a wide range of platforms.
Considering further the interoperation of the software modules in a multimedia application, coded data is passed via the AM 4 from the ACM 7 to a protocol stack 8 which prepares the data for a transfer to the network interface 9. Data is transferred in turn from the network interface 9 to the network transmission channel 10. This transmission channel 10 may be any suitable channel such a land line or an RF wireless connection. In the same way, data received over the transmission channel 10 is passed by the protocol stack 8 via the AM 4 to the ACM 7 for decoding. The decoded data is then passed in pcm form to the ADD 6 to allow the data to be played over the loudspeaker 3 of the soundcard 1.
It has been proposed to replace the soundcard, loudspeaker, and microphone, used for multimedia conversations, with a portable communication device such as a mobile phone coupled to the computer. This generally requires the use in the computer of a dedicated or custom application to interface the phone and the network interface, effectively replacing the AM, ADD, and the ACM described above. If a user wishes to have the choice of using either a soundcard (with associated microphone and loudspeaker) or a portable phone, he must have access to both the custom phone application and the AM/ADD/ACM system.
It is an object of the present invention to provide a computer in which a single application program can be used with both a soundcard and a mobile communication device.
It is a further object of the invention to reduce the computational requirements required of a computer when using the computer to conduct a mutimedia communication.
According to first aspect of the present invention there is provided a method of operating a computer having an audio device driver (ADD) for driving sound control hardware, and an application manager (AM) for interfacing the ADD with an audio compression manager (ACM) to facilitate the transfer of uncompressed audio data between the ADD and ACM and for interfacing the ACM with an external data transfer channel to facilitate the transfer of compressed audio data between the ACM and the external data transfer channel, the method comprising
providing a data transfer manager (DTM) in place of the ACM, the DTM facilitating the transfer of audio data between an external mobile communication device and the external data transmission channel via the AM whilst generating data for use by the AM in interfacing with the ADD.
The present invention increases the potential for offering low-cost internet (and LAN, WAN) telephone calls as an alternative to relatively expensive cellular network calls.
In one embodiment of the invention, the data generated for use in interfacing with the ADD comprises null audio data for playing through a loudspeaker of the sound control hardware.
In an alternative embodiment, the data generated for use in interfacing with the ADD comprises decoded audio data for playing through a loudspeaker of the sound control hardware, wherein audio data is input from the external mobile communication device and output through said loudspeaker to provide a hands-free communication mode.
Preferably, the DTM receives audio data from the sound control hardware via the AM and subsequently discards this audio data.
The present invention provides two significant benefits to users of multimedia applications. Firstly, the DTM is a xe2x80x98bolt-onxe2x80x99 software driver which appears to the AM as a conventional ACM so that a user can select the DTM in the same way as he has always selected a specific ACM. A single AM may therefore be installed on the users computer for conducting communications with either a soundcard based set-up or with a mobile communication device. This has significant cost, flexibility, and familiarity of use advantages. Memory requirements are also reduced.
A further significant and surprising advantage arises from the present invention. In digital mobile communication devices such as mobile phones, audio coding and decoding is carried out in the device. There is thus no need for the computer to perform coding and decoding operations on the audio data, if the data channel supports the phone supported audio coding, and the coded data and the computer may be substantially transparent to this data saving substantial computational effort on the part of the computer. In general, multimedia applications are extremely computationally intensive and the resulting saving is particularly welcome.
Preferably, the DTM is coupled to the external mobile communication device via a custom phone driver. The custom phone driver adapts a vendor specific phone protocol to a computer input-output protocol. Thus, the DTM is made phone independent.
Preferably, the AM transfers data to and from the external data transfer channel via a network communication protocol stack. The protocol stack provides means for controlling connections and for transferring data over the data transfer channel.
Preferably, said sound control hardware is a soundcard. Alternatively for example, this hardware may be integrated into a computer motherboard.
Preferably, the DTM facilitates the transfer of compressed audio data between the external mobile communication device and the external data transmission channel. In one embodiment of the invention, coded audio data is transferred unmodified between the external phone and the external data transfer channel. However, in other embodiments, the DTM may convert coded data received from the data transfer channel in a first format, e.g. G.711, into a second format, e.g. GSM, for transfer to the phone, and vice versa. This may be referred to as xe2x80x98transcodingxe2x80x99.
If required by the AM, the DTM may generate, in addition to said blank uncompressed audio data, control signals for use by the AM.
According to a second aspect of the present invention there is provided a computer having an audio device driver (ADD) for driving sound control hardware, and an application manager (AM) for interfacing the ADD with an audio compression manager (ACM) to facilitate the transfer of uncompressed audio data between the ADD and ACM and for interfacing the ACM with an external data transfer channel to facilitate the transfer of compressed audio data between the ACM and the external data transfer channel, the apparatus comprising a data transfer manager (DTM) in place of the ACM, the DTM facilitating the transfer of audio data between an external mobile communication device and the external data transmission channel via the AM whilst generating data for use by the AM in interfacing with the ADD.
According to a third aspect of the present invention there is provided a storage medium containing thereon a computer program for operating a computer, the computer having an audio device driver (ADD) for driving sound control hardware, and an application manager (AM) for interfacing the ADD with an audio compression manager (ACM) to facilitate the transfer of uncompressed audio data between the ADD and ACM and for interfacing the ACM with an external data transfer channel to facilitate the transfer of compressed audio data between the ACM and the external data transfer channel, said computer program
providing a data transfer manager (DTM) for replacing the ACM, the DTM facilitating the transfer of audio data between an external mobile communication device and the external data transmission channel via the AM whilst generating data for use by the AM in interfacing with the ADD.